WIFI/BLE Simultaneously

ESP_Sprite
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Re: WIFI/BLE Simultaneously

Postby ESP_Sprite » Fri Aug 17, 2018 9:50 am

Ritesh wrote:That means from Hardware side it can not be doable to provide dual WiFi a d Ethernet support. Correct?

If so then we can provide support for that from software side means from stack and application side only.


This has nothing to do with Ethernet. Ethernet doesn't need a radio or a RF-based modulation scheme; WiFi and Ethernet are perfectly usable at the same time, and if you experience performance degradation while using WiFi and Ethernet, it's more likely it's either because the way the software is written or because the speeds are so high the CPU has issues keeping up.

Ritesh
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Re: WIFI/BLE Simultaneously

Postby Ritesh » Fri Aug 17, 2018 10:14 am

ESP_Sprite wrote:
Ritesh wrote:That means from Hardware side it can not be doable to provide dual WiFi a d Ethernet support. Correct?

If so then we can provide support for that from software side means from stack and application side only.


This has nothing to do with Ethernet. Ethernet doesn't need a radio or a RF-based modulation scheme; WiFi and Ethernet are perfectly usable at the same time, and if you experience performance degradation while using WiFi and Ethernet, it's more likely it's either because the way the software is written or because the speeds are so high the CPU has issues keeping up.


Ok. Thanks for Reply.

That is fine that we can use both WiFi and Ethernet together without any issue from hardware and software side.

But let's discuss about BLE and WiFi to use together in which they are sharing single Radio between each other and that can not be doable to use independent WiFi and BLE together. So, We need to manage it from stack or application side. Correct?

Sorry for misunderstanding between WiFi/Eth and WiFi/BLE
Regards,
Ritesh Prajapati

chegewara
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Re: WIFI/BLE Simultaneously

Postby chegewara » Fri Aug 17, 2018 2:56 pm

This is how i see this problem. Lets take simplest application, ble is scanning for devices and wifi is sending gathered informations to server.
At first you have to scan for some short time and stop to give a radio time to wifi stack. Maybe its possible to control this from esp-idf stack, but from my point of view its easier to do this from application code. You can control when you scan, read/write characteristics or descriptors, send notification/indication. There is other side of medal. You can miss notifications or write value from peer device if you are using wifi.

My application is rather simple. Connect to aws IoT with wifi and connect to ble thermal printer. esp32 is subscribed to some IoT topic and when value is what i expect then its printed with printer. There was one more part of code, https client connection, but has been moved to aws lambda because shortage of heap.

I believe you can write app where is not possible use wifi + ble, because both stacks or at least one will require full time radio access, but in other cases its up to programmer to manage "access to radio".
But like i said, its nly my point of view and from my not very big experience and dont have to be right.

Deouss
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Re: WIFI/BLE Simultaneously

Postby Deouss » Sun Aug 19, 2018 3:03 am

From the software side whole process is very complex and seems just crazy.
For example taking scenario when there is BT transfer going and in the middle there is a WiFi request - what happens?
BT stops and WiFi takes over? I assume WiFi must wait for BT to finish or it's some kind of software multiplexing but still antenna gets overlapped signals that may completely disrupt whole transmission.

Ritesh
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Re: WIFI/BLE Simultaneously

Postby Ritesh » Sun Aug 19, 2018 4:23 am

Deouss wrote:From the software side whole process is very complex and seems just crazy.
For example taking scenario when there is BT transfer going and in the middle there is a WiFi request - what happens?
BT stops and WiFi takes over? I assume WiFi must wait for BT to finish or it's some kind of software multiplexing but still antenna gets overlapped signals that may completely disrupt whole transmission.


Yes. I agree that WiFi and Bluetooth both are sharing single gle Radio from Hardware Perspective.

So, We need to manage it from application level to work it smoothly when request comes for both and there might be some delay in communication when requests will come for both at a time.

So, That is completely depends on application developer like which priority he wants to take between WiFi and Bluetooth which depends on your application and product requirement.

Hope this will clear your doubt or query regarding that.
Regards,
Ritesh Prajapati

Deouss
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Re: WIFI/BLE Simultaneously

Postby Deouss » Sun Aug 19, 2018 5:46 pm

Ritesh wrote:
So, We need to manage it from application level to work it smoothly when request comes for both and there might be some delay in communication when requests will come for both at a time.

So, That is completely depends on application developer like which priority he wants to take between WiFi and Bluetooth which depends on your application and product requirement.

Hope this will clear your doubt or query regarding that.


Not exactly, you didn't explain anything related to real hardware-software relationship in deep.
How it is even possible for antenna to filter 2 simultaneous BT/WiFi signals and properly filter them down to the stack?
It does not depend on application because it is not the software issue but strictly hardware.
I would like to see some detailed flowchart how it is done on esp32

Ritesh
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Re: WIFI/BLE Simultaneously

Postby Ritesh » Sun Aug 19, 2018 6:09 pm

Deouss wrote:
Ritesh wrote:
So, We need to manage it from application level to work it smoothly when request comes for both and there might be some delay in communication when requests will come for both at a time.

So, That is completely depends on application developer like which priority he wants to take between WiFi and Bluetooth which depends on your application and product requirement.

Hope this will clear your doubt or query regarding that.


Not exactly, you didn't explain anything related to real hardware-software relationship in deep.
How it is even possible for antenna to filter 2 simultaneous BT/WiFi signals and properly filter them down to the stack?
It does not depend on application because it is not the software issue but strictly hardware.
I would like to see some detailed flowchart how it is done on esp32


Hi,

As Espressif Developer has explained earlier that there is only single shared Radio for WiFi and BLE to operate it from Hardware ESP32 chip and module. So, There is hardware limitation like not able to separate out from Hardware itself.

So, You need to manage it from stack or application side to operate it both simultaneously.

Hope this will clear your doubt regarding that.

Else Espressif Engineer can give better explanation for this.
Regards,
Ritesh Prajapati

Deouss
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Re: WIFI/BLE Simultaneously

Postby Deouss » Sun Aug 19, 2018 8:29 pm

I am not curious about explanation why but how it is done in details in present architecture.
It is very interesting topic about transmissions from shared antenna.

chegewara
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Re: WIFI/BLE Simultaneously

Postby chegewara » Sun Aug 19, 2018 8:36 pm

I am not expert, but in over a year on this forum ive read some about it. This is what i remember:
- wifi and bluetooth are working both on 2.4GHz frequency and are sharing the same radio,
- bluetooth is using channels 37, 38 and 39:
Image
- https://developers.blackberry.com/us/en ... ft+ne+true
Bluetooth operates in the 2.54 GHz band which it shares with Wi-Fi, digital cordless phones and microwave ovens! Bluetooth LE still retains its fundamental resilience by splitting its radio traffic across 40 channels as shown below (Figure 4).

Bluetooth LE Radio traffic hops around these channels in a pseudo random manner so that the data with get through even though it’s in an areas shared by a number of Wi-Fi networks, or microwave ovens. One of the differences between Bluetooth LE and classic Bluetooth is the number and use of these channels.


There is a lot info on internet, just google for "bluetooth radio channels" or similar.

Deouss
Posts: 277
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Re: WIFI/BLE Simultaneously

Postby Deouss » Sun Aug 19, 2018 10:40 pm

I found interesting characteristics of both networks - BT IEEE 802.15 vs WiFi 802.11 standards with various protocols and radio techniques.

A comparison of 802.11ah and 802.15.4 for IoT

Avoiding collisions between IEEE 802.11 and IEEE 802.15.4....

Last article shows there are sensing engines for both protocols that could efficiently separate those two.
Besides there is analog and digital sensing. I just read a part of it - interesting
I am not sure about the costs thou

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